Endocrine cancer in Iran: based on cancer registry system.

BACKGROUND

A population-based registry of endocrine cancer cases in four Iranian provinces, was performed for the years 1996-2000.

MATERIALS AND METHODS

Patients in each province were grouped according to age, gender and tumor specifics (site, morphology, behavior) and the data was coded according to the international classification of diseases for oncology.

STATISTICAL ANALYSIS USED

Person-years of population at risk were calculated and the results were presented as incidence rates by sex, age, age specific rates and age standard rate (ASR) per 100,000 person-years, using direct method of standardization to the world population.

RESULTS

A total of 319 cases of primary endocrine cancer were found and registered, including 313 cases of thyroid carcinoma and 6 cases of adrenal cancer. The thyroid carcinoma group cases consisted of papillary (82.7%), follicular (8.6%), medullary (7.0%) and anaplastic (1.6%) carcinomas. The ASR for thyroid carcinoma was 1.289 (0.627 for men, 1.59 for women), with the highest incidence rate in Kerman (ASR 1.643) and the lowest incidence rate in Golestan (ASR 0.735). For the 6 cases of adrenal cancer, 4 were neuroblastoma and 2 were pheochromocytoma.

CONCLUSIONS

Iran was considered as an endemic, iodine-deficient area, until fairly recently. Iodinization of salt has been started about 12 years ago, in the nation. Considering the effect of improvement in the iodine intake in previously deficient communities, which is associated with an increase in the incidence of papillary carcinoma compared to other histologic types, the frequency and distribution of histologic types of thyroid carcinoma was closer to what can be seen in iodine-rich areas.